The trigone generally has been spared during BTX-A injections because of the theoretical risk of causing vesicoureteral reflux (VUR), but this did not occur in the study, investigators reported at the American Urological Association 2011 annual meeting.

In addition, the study showed that trigonal injections resulted in a longer duration of effect compared with sparing the trigone (eight vs. six months).

The study, by Rustom Manecksha, MD, and collaborators at Adelaide & Meath Hospital in Dublin, included 22 patients with idiopathic detrusor overactivity, 11 who received injections into the trigone and 11 who did not. All patients had failed six or more weeks of anticholinergic therapy. The researchers used the Overactive Bladder Symptom Score (OABSS) questionnaire to evaluate OAB symptoms. The OABSS questionnaire was completed preoperatively and at six, 12, and 26 weeks post-operatively. Trigonal injections were associated with significant greater decreases in OABSS total score at all time points compared with the trigone-sparing approach.